package pkg

import (
	"crypto/sha512"
	"syscall"
)

// A fileArtifact is an [Artifact] that cures into data known ahead of time.
type fileArtifact []byte

var _ KnownChecksum = fileArtifact{}

// NewFile returns a [File] that cures into a caller-supplied byte slice.
//
// Caller must not modify data after NewBin returns.
func NewFile(data []byte) File { return fileArtifact(data) }

// Kind returns the hardcoded [Kind] constant.
func (a fileArtifact) Kind() Kind { return KindFile }

// Params returns the result of Data.
func (a fileArtifact) Params() []byte { return a }

// Dependencies returns a nil slice.
func (a fileArtifact) Dependencies() []Artifact { return nil }

// Checksum computes and returns the checksum of caller-supplied data.
func (a fileArtifact) Checksum() Checksum {
	h := sha512.New384()
	h.Write(a)
	return Checksum(h.Sum(nil))
}

// Data returns the caller-supplied data.
func (a fileArtifact) Data() ([]byte, error) { return a, nil }

// Cure returns syscall.ENOTSUP. Callers should use Data instead.
func (a fileArtifact) Cure(*CureContext) (err error) {
	return syscall.ENOTSUP
}